1. Field of the Invention
The invention relates to an integrated circuit for performing logic operations on at least three input signals which appear together on inputs of the circuit, said circuit comprising at least one current injector provided with a supply electrode for receiving a supply current. A "current injector" is to be understood to mean herein a multi-layer structure, constructed according to semi-conductor technology, comprising at least three layers which are separated from each other by rectifying transitions. Therein, a first, injecting layer is provided with a supply current connection and is separated from the circuit element (elements) to be powered by at least one rectifying transition. Furthermore, a neighbouring second or intermediate layer of semiconductor material which also comprises a supply current connection is provided, so that the connection of a supply current source between said supply current connections (with a polarity which corresponds to the polarity of the rectifying transition between the layers connected thereto) controls an injection of a flow of charge carriers from the injecting to the intermediate layer. Finally, charge carriers are collected in a subsequent, collecting layer of the series of layers of the current injector structure and controlled, via a rectifying transition between said collecting layer and a preceding layer of the current injector structure. One zone of one of the circuit elements to be powered, to be referred to as the zone to be set, which is separated from the injecting layer and its supply current connection by at least two rectifying transitions, is capable of collecting charge carriers from one of the layers of the current injector structure via a rectifying transition which bounds this zone, said zone thus being powered and being connected directly to a pattern of conductor tracks.
2. Description of the Prior Art
A structure of this kind is known as integrated injection logic (I.sup.2 L) and is described in the previous U.S. Patent Application Ser. No. 876,219 in the name of Applicant. The advantages of this structure are extensively described therein and inter alia concern a simple construction and the substantially complete absence of adjusting resistors. Furthermore, there are only few conductor tracks, which enables a compact construction. It is also possible to operate a large number of transistors by means of one and the same current injector, and hence accurately with the same currents. In many cases this is advantageous; for example, if mutually equal switching times of parallel operating elements are required, said switching times being dependent on the supply current. Circuits of this kind also result in technologically attractive manufacturing methods.
Circuits of this kind are frequently used, the aim being for an increasing number of circuit elements per semiconductor body, for example, microprocessors. Circuits of this kind are constructed with elementary components in the form of logic gates which perform AND, OR, NAND, NOR and possibly other logic functions. The inputs of gates of this kind usually have the same rank relative to each other, while a single logic function output is provided, possibly in combination with an output which is inverted with respect thereto.